1. Field of the Invention
The invention relates to a multi-sleeved surgical ultrasonic vibrating tool to perform phacoemulsification. The sleeves channel fluid; there may be an inflexible inner sleeve that serves to reduce friction between itself and the surrounding sleeve, and thereby mitigate against thermal damage to surrounding tissues and channels irrigation fluid to cool the same, a flexible middle sleeve that channels irrigation fluid into the eye, and an outer sleeve to direct fluid to cool ocular tissue external to the incision.
2. Discussion of Related Art
According to the Eye Surgery Education Council of the American Society of Cataract and Refractive Surgery Foundation (http://www.lasikinstitute.org/Phacoemulsification.html), phacoemulsification is the most common and advanced cataract surgery technique.                “The surgeon first makes a small incision at the edge of the cornea and then creates an opening in the membrane that surrounds the cataractous lens. This thin membrane is called the capsule. Next, a small ultrasonic probe is inserted through the opening in the cornea and capsule. The probe's vibrating tip breaks up or “emulsifies” the cloudy lens into tiny fragments that are suctioned out of the capsule by an attachment on the probe tip. After the lens is completely removed, the probe is withdrawn leaving only the clear (now empty) bag-like capsule, which will act as support for the intraocular lens (IOL).        Phacoemulsification allows cataract surgery to be performed through a very small incision in the cornea. Stitches are seldom needed to close this tiny entry, which means that there is less discomfort and quicker recovery of vision than with other surgical techniques. Small incisions do not change the curvature of the cornea like larger ones that were required with older surgical techniques. This allows for more rapid rehabilitation of vision and possibly less dependence on glasses for good distance vision.        After removal of the cataract-damaged lens, an artificial intraocular lens (IOL) is implanted. Made from soft acrylic or solid medical-grade silicone, IOLs are folded so they can be implanted with a small injector, which uses the same incision through which the phaco probe was inserted at the beginning of the procedure. As the IOL is implanted, it unfolds and anchors itself behind the eye's pupil over the remaining clear capsule. The IOLs to be implanted are selected based on power calculations made before surgery.”        
The online Wikipedia describes the surgical technique of phacoemulsification:                “Before the phacoemulsification can be performed, one or more incisions are made in the eye to allow the introduction of surgical instruments. The surgeon then removes the anterior face of the capsule that contains the lens inside the eye. Phacoemulsification surgery involves the use of a machine with microprocessor-controlled fluid dynamics. These can be based on peristaltic or a venturi type of pump.        The phaco probe is an ultrasonic handpiece with a titanium or steel needle. The tip of the needle vibrates at ultrasonic frequency to sculpt and emulsify the cataract while the pump aspirates particles through the tip. In some techniques, a second fine steel instrument called a “chopper” is used from a side port to help with chopping the nucleus into smaller pieces. The cataract is usually broken into two or four pieces and each piece is emulsified and aspirated out with suction. The nucleus emulsification makes it easier to aspirate the particles. After removing all hard central lens nucleus with phacoemulsification, the softer outer lens cortex is removed with suction only.        An irrigation-aspiration probe or a bimanual system is used to aspirate out the remaining peripheral cortical matter, while leaving the posterior capsule intact. As with other cataract extraction procedures, an intraocular lens implant (IOL), is placed into the remaining lens capsule. For implanting a PMMA IOL, the incision has to be enlarged. For implanting a foldable IOL, the incision does not have to be enlarged. The foldable IOL, made of silicone or acrylic of appropriate power is folded either using a holder/folder, or a proprietary insertion device provided along with the IOL.        It is then inserted and placed in the posterior chamber in the capsular bag (in-the-bag implantation). Sometimes, a sulcus implantation may be required because of posterior capsular tears or because of zonulodialysis. Because a smaller incision is required, few or no stitches are needed and the patient's recovery time is usually shorter when using a foldable IOL.”        
Indeed, a common method of cataract removal requires the use of a vibrating ultrasonic needle that can be inserted through a small incision in the human eye. The vibrating needle can cause temperature elevation within the incision. This temperature elevation is a problem that requires certain protective mechanisms, that is, precautions and/or technologies, in order to reduce the possibility of creating a thermal injury to the surrounding ocular tissues. Such protective mechanisms include the creation of an incision that is substantially larger than the ultrasonic needle or probe, with resultant leakage of fluid from the eye around the vibrating tip serving as a coolant. Other protective mechanisms include those previously devised by the applicant, and include the use of a rigid sleeve inserted between the vibrating needle and the soft, pliant outer sleeve through which infusion is delivered into the eye, or the use of an optical device to monitor the temperature in the vicinity of the ultrasonic needle or probe and discontinue needle or probe vibration in the event of undesirable temperature elevation.
There has been interest in performing ultrasonic removal (phacoemulsification) of human cataracts in a manner that divides the location of the entry of the infusion source and the ultrasonic needle into the eye into two smaller incisions in the eye. However, there has been concern that the use of a “bare” ultrasonic needle could increase the risk of thermal injury to the surrounding tissues because of the absence of surrounding rigid sleeves and the fluid contained within such rigid sleeve(s) that normally serve as coolants. It has therefore been advocated and it is the current practice to employ a method in which the surgical incision for insertion of the ultrasonic needle or probe be made substantially larger than that required for insertion of the needle or probe in order to permit fluid leakage from inside the eye to leak alongside the ultrasonic needle and thereby cool the latter.
While such a method will undoubtedly reduce the temperature of the needle, it is not desirable to have fluid leakage from the eye as this increases the trauma inflicted by fluid circulating through the eye during the procedure (a greater amount of fluid passes through the eye during the procedure), control of the pressure within the eye can be compromised by the leakage and this can lead to collapse of the eye, such collapse leading to contact of the vibrating ultrasonic needle with delicate ocular tissues such as the iris, cornea or lens capsule.
Based on the experience of applicant, who has performed tens of thousands of ultrasonic cataract extractions, the greatest risk of thermal injury occurs at the external surface of the incision in the eye where such surface is in contact with the vibrating ultrasonic needle. This appears to be casually related to the fact that the environmental air is a poor conductor of heat away from the eye and the external tissues are therefore more likely to retain thermal energy transferred from the ultrasonic needle.
The present inventor invented the subject matter of U.S. Pat. Nos. 7,762,978 and 7,351,219, which reveals a method and instrumentation for cooling a surgical incision. Indeed, the patented method and instrumentation for cooling the surgical incision enables a degree of cooling to the area of a surgical incision that is more rapid and efficient than air cooling to prevent a temperature rise at the incision to a medically unacceptable level during the use of a surgical device.
It is desirable to provide a degree of cooling to the area of a surgical incision that is more rapid and efficient than that of air cooling to prevent a temperature rise at the incision to a medically unacceptable level during the use of a surgical device, where the surgical device is equipped with one or more sleeves that may include a rigid sleeve that directs fluid to irrigate the eye during phacoemulsification.